Siener R, Jahnen A, Hesse A
Division of Experimental Urology, Department of Urology, University of Bonn, Bonn, Germany.
Eur J Clin Nutr. 2004 Feb;58(2):270-6. doi: 10.1038/sj.ejcn.1601778.
To evaluate the effect of a mineral water rich in magnesium (337 mg/l), calcium (232 mg/l) and bicarbonate (3388 mg/l) on urine composition and the risk of calcium oxalate crystallization.
A total of 12 healthy male volunteers participated in the study. During the baseline phase, subjects collected two 24-h urine samples while on their usual diet. Throughout the control and test phases, lasting 5 days each, the subjects received a standardized diet calculated according to the recommendations. During the control phase, subjects consumed 1.4 l/day of a neutral fruit tea, which was replaced by an equal volume of a mineral water during the test phase. On the follow-up phase, subjects continued to drink 1.4 l/day of the mineral water on their usual diet and collected 24-h urine samples weekly.
During the intake of mineral water, urinary pH, magnesium and citrate excretion increased significantly on both standardized and normal dietary conditions. The mineral water led to a significant increase in urinary calcium excretion only on the standardized diet, and to a significantly higher urinary volume and decreased supersaturation with calcium oxalate only on the usual diet.
The magnesium and bicarbonate content of the mineral water resulted in favorable changes in urinary pH, magnesium and citrate excretion, inhibitors of calcium oxalate stone formation, counterbalancing increased calcium excretion. Since urinary oxalate excretion did not diminish, further studies are necessary to evaluate whether the ingestion of calcium-rich mineral water with, rather than between, meals may complex oxalate in the gut thus limiting intestinal absorption and urinary excretion of calcium and oxalate.
评估富含镁（337毫克/升）、钙（232毫克/升）和碳酸氢盐（3388毫克/升）的矿泉水对尿液成分及草酸钙结晶风险的影响。
共有12名健康男性志愿者参与该研究。在基线期，受试者按日常饮食收集两份24小时尿液样本。在各持续5天的对照期和试验期，受试者接受根据推荐计算的标准化饮食。对照期，受试者每天饮用1.4升中性水果茶，试验期则用等体积的矿泉水替代。在随访期，受试者继续按日常饮食每天饮用1.4升矿泉水，并每周收集24小时尿液样本。
在饮用矿泉水期间，无论是标准化饮食还是正常饮食条件下，尿pH值、镁和柠檬酸盐排泄量均显著增加。仅在标准化饮食时，矿泉水使尿钙排泄量显著增加；仅在日常饮食时，矿泉水使尿量显著增加，草酸钙过饱和度降低。
矿泉水中的镁和碳酸氢盐含量使尿pH值、镁和柠檬酸盐排泄量发生了有利变化，这些都是草酸钙结石形成的抑制剂，抵消了钙排泄量的增加。由于尿草酸排泄量未减少，因此有必要进一步研究评估与餐同服而非餐间饮用富含钙的矿泉水是否可能在肠道内络合草酸，从而限制钙和草酸的肠道吸收及尿排泄。
